Terasaki - Air Circuit Breaker -
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70 Pages

2-3. Installation Precautions

_A CAUTION_

• Electrical work must be done by competent persons.

• Do not place the ACB in such an area that is subject to high temperatures, high humidity, dusty air, corrosive gases, strong vibration and shock, or other unusual conditions. Mounting the ACB in such an area could cause a fire or malfunction.

• Be careful to prevent foreign objects (such as debris, concrete powder, dust, chippings, and iron powder) and oil or rainwater from entering the ACB. These materials inside the ACB could cause a fire or malfunction.

• Prior to commencing any work on the ACB, open an upstream circuit breaker or the like to isolate all sources of power/voltage. Otherwise, electric shock may result.

• Fix the draw-out cradle of the ACB firmly on a flat, level surface using mounting screws. Otherwise, the draw-out operation may cause the breaker body or the draw-out cradle to fall, resulting in damage to the ACB or personal injury. Take care not to deform or bend protrusions in the bottom face of the draw-out cradle when fixing the draw-out cradle with mounting screws. Deformation of the protrusions may cause a malfunction.

• When terminating conductors to the ACB, tighten terminal screws to the torque specified in this manual. Otherwise, a fire could result.

• For 4-pole ACBs, be sure to connect a 3-phase, 4-wire neutral conductor to the N-phase pole (on the right end). Otherwise, an overcurrent may hinder the ACB from tripping, resulting in a fire._

• Do not install the ACB in such an area that is exposed to direct sunlight.

• Make sure that the mounting base has a sufficient capacity of bearing the weight of the ACB (see Table 3 on page 7). The mounting base must be protected against vibration. Take appropriate measures to provide a perfect protection to the mounting base against resonance. Otherwise, open/close operation of the ACB may cause a malfunction of other devices in the switchboard or vibrations of the switchboard may cause a malfunction of the ACB.

• Use the following screws with appropriate length for the main circuit terminals. Main circuit terminal screws: Hex head M10, with flat washers (2), spring washer (1) and nut (1) per screw Tightening torque: 22.5 - 37.2 N-m

Table 1 Number of main circuit terminal screws required

ACB type

AR208S, AR212S, AR216S

AR220S, AR212H, AR216H, AR220H

AR325S, AR332S AR316H, AR320H, AR325H, AR332H

AR440S

Number of main circuit terminal screws (3/4-pole)

Vertical terminals

12/16

18/24

24/32

48/64

Horizontal/front terminals*

12/16

18/24

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Front terminals are not applicable for high-performance ARxxxH types.

• Use the following screw for the ground terminal. The screw must have a length that allows it to be inserted 4 - 9 mm into the ground terminal M8 tapped hole.